Dynamic regulation of phosphorylation of NMDA receptor GluN2B subunit tyrosine residues mediates ketamine rapid antidepressant effects.

The rapid antidepressant effects of ketamine depend on the N-methyl-D-aspartate (NMDA) receptor containing 2B subunit (NR2B), whose function is influenced by its phosphorylated regulation and distribution within and outside synapses. It remains unclear if ketamine's rapid onset of antidepressant effects relies on the dynamic phosphorylated regulation of NR2B within and outside synapses. Here, we show that ketamine rapidlyalleviated depression-like behaviors and normalized abnormal expression of pTyr1472NR2B and striatal-enriched protein tyrosine phosphatase (STEP) 61 within and outside synapses in the medial prefrontal cortex (mPFC) induced by chronic unpredictable stress (CUS) and conditional knockdown of STEP 61, a key phosphatase of NR2B, within 1 hour after administration Together, our results delineate the rapid initiation of ketamine's antidepressant effects results from the restoration of NR2B phosphorylation homeostasis within and outside synapses. The dynamic regulation of phosphorylation of NR2B provides a new perspective for developing new antidepressant strategies.

Diurnal rhythm disruptions induced by chronic unpredictable stress relate to depression-like behaviors in rats.

The relationship between circadian rhythms and mood disorders has been established. Circadian dysregulations are believed to exacerbate the severity of mood disorders and vice versa. Although many studies on diurnal changes of clock genes in animal model of depression have been performed from the RNA level, only a few studies have been carried out from the protein level. In this study, we investigated the diurnal changes induced by chronic unpredictable stress (CUS) using free-running wheel test and Western Blotting (WB). Besides, we examined the depression-like behaviors of rats by sucrose preference test (SPT) and forced swim test (FST). We found that CUS induced significant reductions in the quantity of free-running wheel activity and rhythmic disruptions of clock proteins in hippocampus. Furthermore, we found that the amplitude of PER1 in CA1 was positively related to the severity of depression-like behaviors. These results suggest that CUS results in both changes in diurnal rhythms and in depression-like behaviors and that it is suggested that these changes are related.

Retraction notice to "Diurnal rhythm disruptions induced by chronic unpredictable stress relate to depression-like behaviors in rats" [Pharmacol. Biochem. Behav. 194 (2020) 172939].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor because of serious doubts regarding the data on melatonin levels. The authors used a melatonin ELISA kit that was not fit for purpose, resulting in data showing peak secretion of this hormone occurring in the middle of the light period, which does not make any physiological sense since melatonin is only produced during darkness.

Diurnal rhythm disruptions induced by chronic unpredictable stress relate to depression-like behaviors in rats.

The relationship between circadian rhythms and mood disorders has been established, circadian dysregulations are believed to exacerbate the severity of mood disorders and vice versa. Although many studies on diurnal changes of clock genes in animal model of depression have been performed from the RNA level, only a few studies have been carried out from the protein level. In this study, we investigated the diurnal changes induced by chronic unpredictable stress (CUS) using various methods, including free-running wheel test, enzyme-linked immunosorbent assay (ELISA) and Western Blotting (WB). Besides, we examined the depression-like behaviors of rats by sucrose preference test (SPT) and forced swim test (FST). We found that CUS induced significant reductions in the quantity of free-running wheel activity and the amplitude of melatonin secretion rhythm. We also found that CUS induced rhythmic disruptions of clock proteins in hippocampus. Furthermore, we found that the amplitude of PER1 in CA1 was positively related to the severity of depression-like behaviors. These results suggest that stress results in both changes in circadian rhythms and in depression-like behaviors and that it is suggested that these changes are related.

Effects of rosmarinic acid on immunoregulatory activity and hepatocellular carcinoma cell apoptosis in H22 tumor-bearing mice

Rosmarinic acid (RA) is a natural polyphenolic compound that exists in many medicinal species of Boraginaceae and Lamiaceae. The previous studies have revealed that RA had therapeutic effects on hepatocellular carcinoma (HCC) in the H22-xenograft models by inhibiting the inflammatory cytokines and NF-κB p65 pathway in the tumor microenvironment. However, its molecular mechanisms of immunoregulation and pro-apoptotic effect in HCC have not been fully explored. In the present study, RA at 75, 150, and 300 mg/kg was given to H22 tumor-bearing mice via gavage once a day for 10 days. The results showed that RA can effectively inhibit the tumor growth through regulating the ratio of CD4⁺/CD8⁺ and the secretion of interleukin (IL)-2 and interferon-γ, inhibiting the expressions of IL-6, IL-10 and signal transducer and activator of transcription 3, thereby up-regulating Bax and Caspase-3 and down-regulating Bcl-2. The underlying mechanisms involved regulation of immune response and induction of HCC cell apoptosis. These results may provide a more comprehensive perspective to clarify the anti-tumor mechanism of RA in HCC.

Role of ZHX2 in regulating dorsal root ganglion μ-opioid receptor expression in mice with peripheral nerve injuryinduced pain hypersensitivity / 南方医科大学学报

OBJECTIVE@#To investigate the role of zinc-fingers and homeoboxes 2 (ZHX2) in regulating μ-opioid receptor expression in the dorsal root ganglion (DRG) in mice with peripheral nerve injury-induced pain hypersensitivity.@*METHODS@#Forty-eight male adult C57BL6J mice were randomized into 4 groups and subjected to chronic constriction injury (CCI) of the sciatic nerve or sham operation followed by microinjection of a specific small interfering RNA (siRNA) of ZHX2 or a negative control siRNA sequence (siNC) into the DRG. Seven days later, the mice were examined for changes in the hind paw withdrawal frequency (PWF), after which the DRG tissue was collected for detecting the expressions of μ-opioid receptor at the mRNA and protein levels using RT-qPCR and Western blotting. In another experiment, the DRG tissues were collected from 6 mice (21-day-old) for primary culture of the DRG neurons, which were transfected with ZHX2 siRNA or the siNC to observe the changes in the expressions of ZHX2 and μ-pioid receptor.@*RESULTS@#Microinjection of ZHX2 siRNA into the ipsilateral L3 and L4 DRGs significantly reversed CCI-induced μ-pioid receptor downregulation in the injured DRG and alleviated CCI-induced mechanical allodynia in the mice. In the cell experiment, ZHX2 knockdown obviously upregulated the mRNA and protein expressions of opioid receptor in the primary cultured DRG neurons.@*CONCLUSIONS@#ZHX2 knockdown in the DRG reverses CCI-induced down-regulation of μ opioid receptor to alleviate periphery nerve injury-induced pain hypersensitivity in mice.

Changes in expression of gamma-aminobutyric acid receptor subunit genes in dorsal root ganglia in a mouse model of neuropathic pain / 中华麻醉学杂志

Objective To evaluate the changes in the expression of gamma-aminobutyric acid (GABA) receptor subunit genes in the dorsal root ganglia (DRG) in a mouse model of neuropathic pain. Methods Experiment Ⅰ Twenty-four male C57BL6 mice, aged 8 weeks, weighing 25-30 g, were di-vided into sham operation group (group Sham, n=12) and neuropathic pain group (group NP, n=12) by using a random number table method. Neuropathic pain was produced by bilateral L4 spinal nerve ligation in anesthetized mice in group NP . The mechanical pain threshold of bilateral hindpaws was measured at 1 day before establishing the model and 7 days after establishing the model. Mice were then sacrificed and DRGs of the bilateral L4 were removed to perform transcriptome sequencing and to analyze the expression of GABA receptor subunit genes. Experiment Ⅱ Twenty-four male C57BL6 mice, aged 8 weeks, weighing 25-30 g, were studied. Neuropathic pain was produced by the left L4 spinal nerve ligation in anesthetized mice. Six mice were selected at 1 day before establishing the model and 3, 7 and 14 days after establishing the model, and the mechanical pain threshold of the left hindpaw was measured. Mice were then sacrificed and DRGs of the left L4 were removed to verify the expression of differentially expressed GABA receptor subunitgenes described in experiment Ⅰby quantitative real-time polymerase chain reaction. Results ExperimentⅠ Compared with group Sham, the mechanical pain threshold was significantly increased, the expression of Gabra1, Gabra2, Gabrb3, Gabrg2, Gabbr1 and Gabbr2 in DRGs was down-regulated, and the expres-sion of Gabrg1 in DRGs was up-regulated at 7 days after establishing the model in group NP ( P<0. 05 or 0. 01) . Experiment Ⅱ Compared with the baseline at 1 day before establishing the model, the mechanical pain threshold was significantly increased, and the expression of Gabra1, Gabra2, Gabrb3, Gabrg2, Gab-br1 and Gabbr2 in DRGs was down-regulated at each time point after establishing the model ( P<0. 05 or 0. 01) , and no significant change was found in the expression of Gabrg1 in DRGs at each time point after establishing the model ( P>0. 05) . Conclusion The expression of GABA receptor subunit genes Gabra1, Gabra2, Gabrb3, Gabrg2, Gabbr1 and Gabbr2 in DRGs is down-regulated, and the expression of Gabrg1 in DRGs is up-regulated in a mouse model of neuropathic pain.

Transition temperature of poly(methyl methacrylate) determined by time-of-flight secondary ion mass spectrometry and contact angle measurements.

The surface chain conformations of poly(methyl methacrylate) (PMMA) at different temperatures were extensively studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Similar to our previous experimental studies on polystyrene (PS) and poly(2, 3, 4, 5, 6-pentafluorostyrene) (5FPS), a transition temperature (TT) could be identified through the principal component analysis (PCA) of the ToF-SIMS spectra obtained from the PMMA samples annealed at different temperatures. Interestingly, our results show that the TT depended on molecular weight and was about 50-60˚C below the bulk glass transition temperature (Tg) and therefore could possibly be related to the surface glass transition temperature (TgS). These results were confirmed by contact angle measurements. ToF-SIMS results showed higher peak intensities of several low-mass oxygen-containing positive ions, hydrocarbon positive ions and OCH3- negative ion at higher temperatures, which can be interpreted by a higher surface concentration of methoxy groups at the surface.

Transcription of protein arginine N-methyltransferase genes in mouse dorsal root ganglia following peripheral nerve injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes in the transcription of protein arginine methylation enzyme family genes in the dorsal root ganglia (DRG) following peripheral nerve injury in mice.</p><p><b>METHODS</b>C57BL6 mouse models of neuropathic pain induced by peripheral nerve injury were established by bilateral L4 spinal nerve ligation (SNL). At 7 days after SNL or sham operation, the DRG tissue was collected for transcriptional analysis of 9 protein arginine methylation enzyme genes (Prmt1?3, Carm1, and Prmt5?9) using RNA?Seq to identify the differentially expressed genes in the injured DRGs. We also established mouse models of lateral L4 SNL and models of chronic constriction injury (CCI) of the sciatic nerve and tested the paw withdrawal frequency (PWF) in response to mechanical stimulation and paw withdrawal latency (PWL) in response to thermal stimulation on 0, 3, 7 and 14 days after SNL or CCI; the expressions of the differentially expressed genes in the injured DRGs were verified in the two models using RT?qPCR.</p><p><b>RESULTS</b>Among the 9 protein arginine methylation enzyme family genes that were tissue?specifically expressed in the DRG, Prmt2 and Prmt3 showed the highest and Prmt6 showed the lowest basal expression. Compared with the sham?operated mice group, the mice receiving SNL exhibited upregulated Carm1 gene transcription (by 1.7 folds) but downregulated Prmt5, Prmt8 and Prmt9 transcription in the injured DRG (Prmt8 gene showed the most significant down?regulation by 16.3 folds). In mouse models of SNL and CCI, Carm1 gene expression increased progressively with time while Prmt8 transcription was obviously lowered on days 3, 7 and 14 after the injury; the transcription levels of Prmt1, Prmt5 and Prmt9 presented with no significant changes following the injuries. Both SNL and CCI induced mechanical allodynia and thermal hypersensitivities in the mice shown by increased PWF and decreased PWL on days 3, 7 and 14 after the injuries.</p><p><b>CONCLUSION</b>Periphery nerve injury induces Carm1 upregulation and Prmt8 downregulation in the injured DRG in mice, which sheds light on new targets for treatment of neuropathic pain.</p>

Effects of Polysaccharides from Millettia speciosa Champ on Proliferation of Spleen Lymphocyte and Secretion of Cytokine in Mice / 医药导报

Objective To explore the mechanism of immunoregulation by investigating the effects of polysaccharides from Millettia speciosa Champ (MSC) on proliferation of spleen lymphocyte and secretion of cytokine in mice.Methods The effects of MSC polysaccharides on Con A-induced spleen T lymphocyte proliferation were determined by MTT.The contents of TNF-α, IL-6 and PGE2 were determined by ELISA.Results The Con A-induced T lymphocyte proliferation was significantly increased by MSC polysaccharides at the concentrations from 50 to 200 μg·mL-1.Coupled with TNF-α and IL-6 were significantly increased while PGE2 was significantly decreased.Conclusion MSC polysaccharides could increase proliferation of spleen lymphocyte and enhance the immune responses by increasing the secretion of TNF-α and IL-6 in mice.

Comparison pharmacodynamics of continuous or intermittent cisatracurium infusion during laparoscopy for deep neuromuscular blockade / 临床麻醉学杂志

Objective To investigate continuous infusion and inermittent injection of cisatra-curium for deep neuromuscular blockade during laparoscopic surgery and to compare the effectiveness and safety.Methods Sixty ASA Ⅰ or Ⅱ patients,aged from 18 to 65,undergoing selective laparo-scopic gastrointestinal surgery with general anesthesia were randomly divided into 2 groups:group A (n =30)received cisatracurium 0.1 5 mg/kg for intubation,and then continuous infusion of cisatra-curium with micropump at an original rate of 0.2 mg·kg-1 ·h-1 when post tetanic count (PTC)≥3;group B(n =30)was given cisatracurium 0.1 5 mg/kg for intubation,and then intermittent infusion of cisatracurium of 0.05 mg/kg when PTC≥ 3.The cisatracurium consumption,duration of neuro-muscular blocking agent used in group A from induction to the end of infusion and in group B from in-duction to the last infusion,satisfaction of neuromuscular blockade (grade 0-10)of the surgeons,the time of T1 recovered to 25%,75%,TOFr recovered to 0.7,0.9,fulfillment of tongue depressor test,the incidence of hyoxemia after extubation,pneumonia,atelectasis were recorded.Results In comparison with group B,the cisatracurium consumption in group A was significantly more (P <0.05),and the satisfaction of the surgeons was significantly higher at the beginning,1 h,2 h of the operation (P <0.05).The satisfaction of the surgeons respectively showing no significant differences between the two groups at the end of the operation.Recovery index (T1 from 25% to 75%),time of TOFr recovery to 0.7,0.9 in group A was increased,but not statistically.Two patients (7.1%)in group A had hyoxemia after extubation while 1 (4.2%)in group B,the incidence rate was not signifi-cant;3 patients (10.7%)in group A was unable to perform sustained tongue depressor test while 4 (1 6.7%)in group B,the incidence was not significant;all of the patients did not suffer pneumonia and atelectasis.Conclusion Continuous infusion cisatracurium during laparoscopic procedures for deep neuromuscular blockade is effective and safe.The dose of cisatracurium is bigger,and muscular relax-ation would be deeper compared to intermittent infusion.Continuous infusion may prolong the working time of muscle relaxant,but have on influence on the residual effect of muscle relaxant.

Effect of preemptive local injection of ropivocaine with dexmedetomidine on mirror pain in rats and its mechanism

Objective: To observe the effect of preemptive local injection of ropivocaine with dexmedetomidine on activation of glial cells and on the mirror pain in rats and its mechanism. Methods: A total of 48 adult male Sprague-Dawley rats (weighing 180 g-220 g) were included in the study and randomized into 3 groups, Group S, Group R, and Group RD

Effect of preemptive local injection of ropivocaine with dexmedetomidine on mirror pain in rats and its mechanism

OBJECTIVE@#To observe the effect of preemptive local injection of ropivocaine with dexmedetomidine on activation of glial cells and on the mirror pain in rats and its mechanism.@*METHODS@#A total of 48 adult male Sprague-Dawley rats (weighing 180 g-220 g) were included in the study and randomized into 3 groups, Group S, Group R, and Group RD1. A rat model of persistent postoperative pain evoked by skin/muscle incision and retraction was established in the three groups. Before procedures and nerve extraction, Group S (n = 16) was injected 0.9% saline locally; Group R (n = 16) was injected 0.5% ropivocaine locally, and Group RD1 (n = 16) was injected 0.5% ropivocaine in combined with 1 μg dexmedetomidine locally. After the model being established in the three groups, 8 rats were used for behavior test until 28 d, and dorsal root ganglions (DRGs) of the other 8 rats were harvested on the 3rd day after surgery. Immunofluorescent and transmission electron microscopy were used to observe the activation of glial cells in DRG, and the behavior test results in the three groups were compared.@*RESULTS@#The results showed that mechanical pain threshold in ipsilateral hind-paws of the Group S, Group R, Group RD1 animals dropped to (3.640 ± 1.963) g, (5.827 ± 1.204) g, (7.482) ± 1.412 g at 3 d respectively; while in contralateral paws dropped to (7.100 ± 1.789) g, (17.687 ± 1.112) g, (16.213 ± 1.345) g on the 3 d respectively. Immunofluorescent showed that the glial cells were activated in bilateral side DRG after surgery in 3 groups, but ipsilateral paws expressed more active glial cells than contralateral paws. Transmission electron microscopy showed that mitochondria swelling/vacuolization and lysosomes were more obvious in ipsilateral paws than contralateral paws, but Group RD1 formula could reduce glial cells activity, mitochondria swelling/vacuolization and the amount of lysosomes.@*CONCLUSIONS@#Local injection of ropivocaine and/or dexmedetomidine can effectively inhibit the activation of glial cells in DRG, mitigate the pathological changes of neuron in DRG and reduce mirror image pain.

Detection of surface mobility of poly (2, 3, 4, 5, 6-pentafluorostyrene) films by in situ variable-temperature ToF-SIMS and contact angle measurements.

Poly (2, 3, 4, 5, 6-pentafluorostyrene) (5FPS) was prepared by bulk radical polymerization. The spin-cast films of this polymer were analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS) at various temperatures ranging from room temperature to 120°C. Principal component analysis (PCA) of the ToF-SIMS data revealed a transition temperature (T(T)) at which the surface structure of 5FPS was rearranged. A comparison between the results of the PCA of ToF-SIMS spectra obtained on 5FPS and polystyrene (PS) indicate that the pendant groups of 5FPS and PS moved in exactly opposite directions as the temperature increased. More pendant groups of 5FPS and PS migrated from the bulk to the surface and verse versa, respectively, as the temperature increased. These results clearly support the view that the abrupt changes in the normalized principal component 1 value was caused by the surface reorientation of the polymers and not by a change in the ion fragmentation mechanism at temperatures above the T(T). Contact angle measurement, which is another extremely surface sensitive technique, was used to monitor the change in the surface tension as a function of temperature. A clear T(T) was determined by the contact angle measurements. The T(T) values determined by contact angle measurements and ToF-SIMS were very similar.

Synthesis and photoluminescent properties of NaYF4:Eu3+ core and NaYF4:Eu3+/NaYF4 core/shell nanocrystals.

NaYF4:Eu3+ core and NaYF4:Eu3+/NaYF4 core/shell nanocrystals (NCs) were synthesized via a wet chemical method. The transmission electron microscope photographs show that the core and core/shell nanoparticles are monodisperse and uniform NCs with average diameters of 22 and 26 nm respectively. The photoluminescence (PL) properties of the samples, including the PL excitation and emission spectra, and luminescent decay curves, are investigated in detail. The results show that the intensity of 5D2 emission relative to that of 5D0 is stronger in NaYF4:Eu3+/NaYF4 core/shell NCs than that in NaYF4:Eu3+ core NCs, and a longer decay lifetime of 5D2 is observed in core/shell samples. In addition, from the corrected emission spectra of 5D0, the 5D0 radiative lifetimes were calculated. These together with the measured decay lifetime of 5D0 emission give the intrinsic quantum yields of 5D0. The results were well interpreted by considering the surface effects.

Comparison of pharmacodynamics of rocuronium administered by intermittent bolus injection according to body surface area and real body weight / 实用医学杂志

Objective To compare the pharmacodynamics of rocuronium intermittently administered according to body surface area and real body weight and individual differences. Method Forty-two patients undergoing elective surgery under general anesthesia were enrolled into the body surface area group (BSA group) and the real body weight group (RBW group), with 21 patients in each group. The patients in the two groups were induced with 2ED95 of rocuronium according to body surface area and real body weight (16.64 mg/m2 in BSA group; 0.6 mg/kg in RBW group). Whenever T1 recovered to 10%, a dosage of 0.5ED95 was administred repeatedly for 30 min before the end of the operation. The time of neuromuscular blockade and recovery of muscle relaxation were recorded, and the dosage of rocuronium was also recorded. Results No significant difference in each index of neuromuscular block time-effect was found between the two groups (P > 0.05). The single dosage and maintainance amount of muscle relaxation were less in the BSA group than that in RBW group (P < 0.05). Compared with the RBW group, the single dosage, dosing intervals, pharmacological duration and the time TOFr recovered to 0.7 between the different individuals were less in the BSA group (P < 0.05). Conclusion The intermittent administration of rocuronium can maintain the same clinical efficacy according to body surface area as that according to real body weight , with significantly less dosageand reducing the differences of individuals in blockade time-effect of muscle relaxation.

Pharmacodynamics comparative of cis-atracurium intermittent bolus injected according to real body weight and fat-free mass / 实用医学杂志

Ojective To compara the individual differences and clinical efficacy of cis-atracurium intermittent bolus injected according to fat-free mass and real body weight. Methods Forty patients (ASAI-II) who had no neuromuscular disease and underwent selective abdominal surgery under general anesthesia were randomly divided into group FFM (n=20) and group RBW(n=20) according to the different administration method. The responses of adductor pollicis to train-of-four (TOF) stimulation were monitored. Anesthesia was induced with propofol 2 mg/kg, fentanyl 3 ug/kg, cis-atracurium 129.6μg/kg (group FFM) or 100μg /kg (group RBW),and maintained with propofol and fentanyl given by target-controlled infusion. Intubation was attempted when T1 reached maximal inhibition. When the TOF stimulus T1 recovery to 5%, both group additional cis-atracurium 64.8 μg/kg (group FFM) or 50μg /kg (group RBW). The onset time, nonresponsive time, clinical duration, recovery index, pharmacological duration, cis-atracurium consumption, interval and frequency were recorded. Results No significant differences were found in general, interval, frequency,onset time, clinical duration, nonresponsive time,recovery index, pharmacological duration between the two groups (P > 0.05); There were significant differences in the cisatracurium consumption between two groups (P < 0.05); Compare with the group RBW, the differences of pharmacological duration and nonresponsive time between different individuals in group FFM were smaller (P < 0.05). Conclusion It can reduce the individual differences of muscle relaxant effect to apply cis-atracurium and cis-atracurium consumption according to fat-free mass.

Evidence of enhanced mobility at the free surface of supported polymer films by in situ variable-temperature time-of-flight-secondary ion mass spectrometry.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra of polystyrene (PS) films supported on silicon wafers were obtained at temperatures ranging from room temperature to 100 °C. Principal component analysis (PCA) of the TOF-SIMS data revealed a transition temperature (TT) at which the surface structure of PS was rearranged. The TT of a 120-nm thick PS (weight-average molecular weight of 3,000 g/mol) thin film was determined to be about 36 °C, which is approximately 30 °C lower than the bulk glass transition temperature (Tg) of that PS. Similar TTs were observed on PSs with different molecular weights. As the TT is strongly related to the Tg and dependent on the molecular weight, it is believed that the TT determined by TOF-SIMS is related to the surface glass transition temperature (Tg(S)) measured by other techniques. This suggests that TOF-SIMS combined with PCA can be used to determine the Tg(S) of polymer films. Furthermore, the detailed PCA analyses indicate that the phenyl groups of PS tended to move away from the surface at temperatures above TT. This conclusion was further confirmed by contact angle and XPS measurements.

Hollow interior structure of spin-coated polymer thin films revealed by ToF-SIMS three-dimensional imaging.

Surface patterns were observed on spin-coated poly(bisphenol A decane ether) (BA-C10) films prepared with chloroform and tetrahydrofuran as the solvents. The interior structure of these surface patterns were analyzed using a time-of-flight secondary ion mass spectrometry (ToF-SIMS) equipped with a bismuth cluster source for ion imaging and a C(60)(+) cluster source for depth profiling. For the first time, the surface patterns have been shown to be hollow rather than solid using ToF-SIMS three-dimensional (3D) analysis and optical techniques. Moreover, the microarea depth profiling analysis indicated that the hollow structure was sandwiched between two polymer layers rather than sitting on the substrate. The height of the hollow structure and the thicknesses of the polymer layers above and below the hollow structure were also estimated from the depth profiling results.

High-impact polystyrene/halloysite nanocomposites prepared by emulsion polymerization using sodium dodecyl sulfate as surfactant.

High-impact polystyrene (PS) nanocomposites filled with individually dispersed halloysite nanotubes (HNTs) were prepared by emulsion polymerization of styrene in the presence of HNTs with sodium dodecyl sulfate (SDS) as the emulsifier. The SDS is a good dispersing agent for HNTs in aqueous solution. The emulsion polymerization resulted in the formation of polystyrene nanospheres separating individual HNTs. Transmission electron microscopy revealed that the HNTs were uniformly dispersed in the PS matrix. Differential scanning calorimetry, Fourier-transform infrared spectroscopy and thermogravimetry were used to characterize the PS/HNT nanocomposites. The impact strength of the PS/HNTs nanocomposites was 300% higher than that of the neat PS. This paper presents a simple yet feasible method for the preparation of high-impact PS/halloysite nanocomposites.